Loss of Vision

• Diagram courtesy of Merk.com.
  
  Loss of vision is the main symptom of eye nerve damage. Each eye has its own optic nerve. On the way to the brain, the two optic nerves meet. Each optic nerve then splits into two, creating four nerve pathways. As they split, half of the optic nerve fibers from each eye cross over to the other side.
  
  

Damage to One Optic Nerve

• Sometimes only one optic nerve is damaged, and the damage happens between the eye and the optic chiasm (where the two nerves meet). In this case, the sight loss will occur in only one eye.
  
  

Damage at the Optic Chiasm

• In other cases, the nerve damage is located where the two nerves meet. In this situation, you will lose the outer or peripheral field of vision. In other words, you can see straight ahead, but not out to the side.
  
  

Damage Closer to the Brain

• If the nerve damage occurs between the optic chiasm and the brain, part of the visual field will be lost in both eyes. Since the nerves split and cross sides at the optic chiasm, the area of visual loss will depend on the exact location of the damage.
  
  

Other Symptoms

• In some cases, you may experience eye pain especially when moving the eye. A loss of color vision can also occur. If there is severe damage to the nerve, blindness results.
  
  

Causes

• Certain medical conditions can cause damage to the optic nerve. This includes glaucoma, high blood pressure, diabetes and damage resulting from a stroke. Other causes include multiple sclerosis, head injuries or an injury that fractures the bones around the eye.